bore/stroking 2.5L

[944lover]

What all is involved in boring or stroking a 2.5L non turbo 944? What is the difference between boring and stroking? What kind of increase in performance might be gained, and how much would it cost? Also, where could I get it done, and what else might need to be done to the car?

PS what I am really after is better acceleration...

[87Porsche951]

When you bore you hav to take the block to a machinist to overbore it what every specs you you want and are possible. When you stroke it you put in a crank that has a bigger stroke like a S2/968 3.0L crank but also need smaller connecting rods.

What are you wanting to increase displacement to?

you can bore the 100MM bores to 106MM and get 2.8L. you can put a S2/968 crank and get 2.8L i think. you can bore to 106MM & do S2/968 crank and get 3.0L and i think 110MM bore & S2/968 crank and i think you will be at 3.4L not sure though. Its expensive either way. I think the least expensive way is to do just do a overbore that way all you need is bigger pistons and you can use same connecting rods but i would spend the money for new rods.

All methods will better acceliration. Stroker will give you more tq at lower rpm to give you better offline acceliration. Im planning on doing a all bore 2.8L myself. Im not worried about offline acceliratio as the car isnt a drag car im just wanting mid to high rpm performance.

[944lover]

well, I'm most interested in more mid range, for passing (also thinkin about doing some track days so mid/high would be more important than off the line accel.). Course I would like to improve a bit on that 8.3s 0-60 that the n/a has..... Correct me if I am wrong, but it seems to me that new rods/crank would be a more important upgrade though...also, if I bore/stroke I'll probably do some other stuff like MAF, cam, exhaust; with all that stuff plus the bore/stroke what would I need to do about the stock ECU? Where can I get shorter connecting rods.....would they have to be custom?